Why is the correct counter for rabbits 羽（わ）

Question

Why is the correct counter for rabbits 羽（わ）, the counter that is used for birds.

I figured it is because they jump, cause fly and jump are the same verb in Japanese, but then frogs are 匹.

Answer 1

I also heard the Buddhist monk story, but another theory is that while the word ウサギ is theorized to have come to Japanese from a Sanskrit origin through Korea, it was reinterpreted by some as う+鷺, providing a linguistic connection to birds and to the 羽 counter.

Answer 2

The usual story is that Japanese Buddhist monks, who were unable to eat meat other than birds, liked the taste of rabbit so much that they "reclassified" them as flightless birds due to their various body features.

Answer 3

The Sanskrit origin feels most satisfying, but I'll add one more that Wikipedia mentions: hunters would carry their kills by the ears, tying them up and carrying them in bundles. One bundle would be 一把 (いちわ), two 二把...supposedly counting rabbits in this way, わ became associated with 羽.

Answer 4

I'd like to add a note about the etymology of うさぎ, which is touched upon in multiple posts on this thread.

Theories of a compound seem unlikely

Some sources (Nihon Jiten, Gogen Yurai Jiten) describe modern うさぎ as a compound of ancient う ("rabbit") plus native Japanese term 鷺【さぎ】 ("white egret or heron") in reference to the white color.

• Rabbits generally aren't white. In fact, the word for "rabbit; hare" in English and many other languages traces back to a Proto-Indo-European root meaning "grey", a more common color for hares and rabbits.

These same references describe an alternative origin for the sagi ending in a borrowing from Sansrkit sasaka.

• This is also problematic, as Sanskrit terms were generally higher-register as part of the Buddhist tradition, and were not widely used for compounding.
• In addition, the Sanskrit term शशक (śaśaka) includes the consonant value //ɕ//, basically identical to the consonant in Japanese し, and thus would likely have been borrowed as シャシャカ, not ササカ.
• Also, this Sanskrit term is a derived diminutive form of base noun शश (śaśa), adding the diminutive suffix -क (-ka). Even assuming that this derived form might have been borrowed into early Japanese, I can find no clear and compelling mechanism or reason for an ending -ka to metamorphose into -gi.

Ancient forms and evidence in Eastern Old Japanese

While those sources point to う as the oldest form of the word for "rabbit", this isn't strictly true, from what I can find. The 兎【う】 entry in the 日本国語大辞典【にほんこくごだいじてん】 (NKD) dictionary cites this to a passage in the 日本書紀【にほんしょき】 of 720:

問菟。此云塗毘宇。菟穗名。此云宇保那。

In both cases, the Chinese term 菟 is rendered in phonetic Old Japanese as 宇 or u. 塗毘宇 or tobiu is presumably a precursor to modern 跳兎【とびうさぎ】, but I have no idea what 宇保那 or upona is supposed to be. While this does show u used to mean "rabbit", there are cases in Old Japanese of terms used in abbreviation, such as 坂 saka abbreviated to just sa.

In addition, the 万葉集【まんようしゅう】 collection of poetry was completed in 759 and includes poems dating back another hundred years or so. Poem 3529 records the eastern dialectal Japanese word for "rabbit" in phonetic man'yōgana as 乎佐藝【をさぎ】. Eastern Japanese would be even less likely to include borrowed and compounded Sanskrit words.

Possible cognates outside of Japan

Looking outside of Japonic, the Korean word for "rabbit" is 토끼 (tokki), from older Middle Korean 톳〮기〮 (thwóskí), with dialectal variant *투ᄭᅵ〮 (*thwùskí). This in turn has been linked to modern Oroqen term tʊkʃakɪ, and reconstructed proto-Tungusic *tuksaki ("hare"), apparently a derivation from *tuksa ("to run") + nominalizing suffix -ki.

While certainly not a perfect match, there may be room for Japonic wosagi or usagi to be related to Tungusic *tuksaki or descendant Middle Korean term thwóskí and dialectal form thwùskí. The latter even comes close to aligning with the pitch accent pattern of modern Japanese [うさぎ]{LHH}.

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Counters

As far as the choice of counters goes, I haven't seen anything in my references, but my personal theory is that this was at least partly influenced by the way a rabbit's ears stick up, not too terribly unlike the 羽 pictogram of wings.

FWIW, the NKD entry for 羽【わ】 cites a text from 1548 for the first appearance of this used as a counter, which is much later than the first appearance of the word usagi.

Answer 5

羽(わ) is used because there is some stories that rabbit live in Moon, but using 匹（ひき）is also not wrong, and even sometimes used 一耳(ひとみみ）.

Jump and Fly both can read as とぶ、but they have different Kanjis 跳ぶ, 飛ぶ. actually, so may be that's not the reason, I think ....

Answer 6

When I lived in Japan 40 years ago it was explained to me that in feudal times the peasants were forbidden to eat animals, only birds, fish etc. But as rabbits were in plentiful supply in a typically Japanese way they used the bird counter as a solution to allow themselves to eat rabbits without penalty. Whether that’s true or not I don’t know but it was a good story.